1/2+1/6+1/12+1/24+1/30
=(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6
=1-1/6
=5/6
猜你喜欢
- 1No one is so omnipotent that he does not need help once in a while是什么意思啊?
- 2求由方程ye^x+lny=1所确定的隐函数y=y(x)的二阶导数(d^2y)/(dx^2)
- 3函数f(x)=x^2-2ax+1在[1,3]上的最大值为4,则实数a=?
- 4完成下面的句子,每空一词 One day ,Tom took his little brother Sam to go to the cinema .It was a
- 5现在完成时的时间状语
- 6I am a student,( A.isn't I B.am I C.aren't I D.don't I
- 73/5的倒数加上一个小数等于最小的质数,这个数是多少?
- 8有X2、XY3两种物质,使12gX2与足量的XY3反应生成24gXY,反应方程式为X2+XY3═3XY,则X、Y两元素相对原子质量之比为( ) A.1:1 B.2:1 C.3:1 D.4:1
- 9Rt△ABC中,∠C=90°,AC=6,BC=8,则△ABC的内切圆半径r=( ) A.1 B.2 C.3 D.5
- 10设f(y)连续,证明∫a→b dx∫a→x f(y)dy=∫a→b f(y)(b-y)dy